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	<head>
		<title>three.js webgpu - texture gradient</title>
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		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="example.css">
	</head>
	<body>

		<div id="info">
			<a href="https://threejs.org/" target="_blank" rel="noopener" class="logo-link"></a>

			<div class="title-wrapper">
				<a href="https://threejs.org/" target="_blank" rel="noopener">three.js</a><span>Texture Gradient</span>
			</div>

			<small>
				This example demonstrate texture gradient
				<br /> Left canvas is using WebGPU Backend, right canvas is WebGL Backend.
				<br /> The bottom half of the texture benefits from the gradient to achieve better blur quality.
			</small>
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/webgpu": "../build/three.webgpu.js",
					"three/tsl": "../build/three.tsl.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three/webgpu';
			import { If, vec4, float, time, cos, pow, vec2, uv, texture, Fn } from 'three/tsl';

			// WebGPU Backend
			init();

			// WebGL Backend
			init( true );

			async function init( forceWebGL = false ) {

				const aspect = ( window.innerWidth / 2 ) / window.innerHeight;
				const camera = new THREE.OrthographicCamera( - aspect, aspect );
				camera.position.z = 2;

				const scene = new THREE.Scene();

				// texture

				const material = new THREE.MeshBasicNodeMaterial( { color: 0xffffff } );

				// load async brick_diffuse
				const map = await new THREE.TextureLoader().loadAsync( 'textures/uv_grid_opengl.jpg' );

				material.colorNode = Fn( () => {

					const color = vec4( 1. ).toVar();

					const vuv = uv().toVar();
					const blur = pow( float( 0.0625 ).sub( cos( vuv.x.mul( 20.0 ).add( time ) ) ).mul( 0.0625 ), 2.0 );

					const grad = vec2( blur ).toVar();

					If( vuv.y.greaterThan( 0.5 ), () => {

						grad.assign( 0 );
			
					} );

					color.assign(
						texture( map, vuv.add( vec2( blur, blur ).mul( 0.5 ) ) ).grad( grad, grad ).mul( 0.25 )
							.add( texture( map, vuv.add( vec2( blur, blur.negate() ).mul( 0.5 ) ) ).grad( grad, grad ).mul( 0.25 ) )
							.add( texture( map, vuv.add( vec2( blur.negate(), blur ).mul( 0.5 ) ) ).grad( grad, grad ).mul( 0.25 ) )
							.add( texture( map, vuv.add( vec2( blur.negate(), blur.negate() ).mul( 0.5 ) ) ).grad( grad, grad ).mul( 0.25 ) )
					);


					If( vuv.y.greaterThan( 0.497 ).and( vuv.y.lessThan( 0.503 ) ), () => {

						color.assign( 1 );

					} );
			

					return color;

				} )();
			
				//

				const box = new THREE.Mesh( new THREE.PlaneGeometry( 1, 1 ), material );
				scene.add( box );

				const renderer = new THREE.WebGPURenderer( { antialias: false, forceWebGL: forceWebGL } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth / 2, window.innerHeight );
				renderer.setAnimationLoop( animate );

				document.body.appendChild( renderer.domElement );
				renderer.domElement.style.position = 'absolute';
				renderer.domElement.style.top = '0';
				renderer.domElement.style.left = '0';
				renderer.domElement.style.width = '50%';
				renderer.domElement.style.height = '100%';

				if ( forceWebGL ) {

					renderer.domElement.style.left = '50%';

					scene.background = new THREE.Color( 0x212121 );
			
				} else {

					scene.background = new THREE.Color( 0x313131 );

				}

				//

				function animate() {

					renderer.render( scene, camera );
			
				}

				window.addEventListener( 'resize', onWindowResize );

				function onWindowResize() {

					renderer.setSize( window.innerWidth / 2, window.innerHeight );

					const aspect = ( window.innerWidth / 2 ) / window.innerHeight;

					const frustumHeight = camera.top - camera.bottom;

					camera.left = - frustumHeight * aspect / 2;
					camera.right = frustumHeight * aspect / 2;

					camera.updateProjectionMatrix();

					renderer.render( scene, camera );

				}

			}

		</script>
	</body>
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